Russian Soyuz Rocket launches Next-Generation Glonass Satellite

November 30, 2014

A Soyuz
2-1B rocket blasted off from Site 43/4 a the Plesetsk Cosmodrome, Russia’s
primary military launch site, at 21:52 UTC on Sunday embarking on a three and a
half-hour mission to deliver the Glonass-K1 #12 navigation satellite to an
orbit over 19,000 Kilometers in altitude. Confirmation of launch success was provided by Russian media outlets after the satellite was delivered to the planned orbit, separating from the launcher at 1:25 UTC on Monday.The
Glonass-K1 #12 satellite is the second of two prototype satellites of the third
generation of Glonass spacecraft that operate like its American counterpart,
the Global Positioning System. Introduced in the 1980s, Glonass went through
several upgrades over the years as the satellite fleet was modernized and is
currently in its second generation using the Glonass-M spacecraft. Glonass-K
satellites use modern spacecraft systems to prolong the spacecraft’s operational
life and inaugurate new navigation signals to enhance the accuracy of the
Glonass system.

*File Image* - Photo: Russian Ministry of Defence

The new generation of Glonass satellites switch from an older pressurized satellite bus to the unpressurized Ekspress-1000K bus built by ISS Reshetnev, reducing the mass of the satellites from 1,500 to just 935 Kilograms which will allow two spacecraft to be launched atop a Soyuz rocket once the operational Glonass-K2 satellites begin deployment.

Photo: ISS Reshetnev

First Glonass-K

The
first Glonass-K1 satellite was launched in 2011 after a series of
delays suffered by the project. Beginning operations, the first
Glonass-K spacecraft demonstrated the functionality of the new satellite
bus as well as the new L-3 CDMA signal. The launch of the second
prototype satellite was expected within one year of the first one,
however, problems with the satellite and its launch vehicle’s Fregat
upper stage pushed the launch into 2013. Glonass-K1 #12 had to take the
back seat in 2013 and 2014 because launches of
Glonass-M satellites took priority to keep the satellite constellation
in an operational condition after the losses of spacecraft suffered in
Proton launch failures in 2010 and 2013.Completing
a long road to the launch pad, the second Glonass-K1 satellite was
finally rolled out on Friday to begin final preparations for its
late-night blastoff from Russia’s northern launch site using the trusted Soyuz rocket. Completing two
days of launch preparations, teams headed into the eight-hour countdown
sequence that started with the installation of batteries on the Soyuz
booster and the removal of protective covers from the rocket’s first
stage engines.

Teams also wet through fueling preparations and conducted a number of health checks on the Soyuz launch vehicle and Fregat upper stage. The tanking cars pulled up to the launch pad and were hooked up to fueling systems earlier in the day to initiate propellant loading on the Soyuz at L-4 hours. After chilldown of liquid Oxygen ground systems, transfer lines and the tanks of the Soyuz, the -183°C LOX started flowing into the six oxidizer tanks of the rocket. A short time later, the boosters, core stage and third stage began Kerosene loading as well. For liftoff, Soyuz 2-1B is loaded with a total of 274,140 Kilograms of propellants.Soyuz 2-1B is one of two modernized versions of the workhorse of the Russian & Soviet Space Programs using the well-known design of the Soyuz consisting of a large core stage with four-liquid fueled boosters strapped to it and a Block I upper stage installed atop. Overall, Soyuz 2-1B stands 46.1 meters tall weighing 308,000 Kilograms when fully fueled for launch.

Fueling
was complete by L-1 hour and 45 minutes which signaled the start of a
thorough set of launch vehicle checkouts including electrical testing,
control system verifications and communication checks. Inside one hour
to liftoff, the two halves of the Service Structure were retracted and
lowered to their launch position to clear the way for the Soyuz rocket.
The
Liftoff of Soyuz 2-1B was preceded by the Automated Countdown Sequence
that included the final steps to prepare the vehicle for launch such
as the pressurization of propellant tanks, the handover of control to
the onboard computers, the transfer to internal power, and the purge of
the engines to condition them for ignition 20 seconds before liftoff.With
a total thrust of 422 metric tons, the Soyuz started rising from its
pad at 21:52 UTC to begin its journey into orbit – powered by the
RD-107A engines on the four boosters and the RS-108A on the core stage.
Soyuz climbed vertically for a few seconds before making a pitch and roll
maneuver to start heading south-east, en-route to an orbit inclined
64.8 degrees. Consuming 1,600 Kilograms of propellants per second,
Soyuz lit up the night skies over Russia.The
four boosters operated for one minute and 58 seconds, burning nearly
40 metric tons of propellant each to deliver extra thrust during the
initial phase of the flight. Shutting down their engines, the boosters
were separated by pyrotechnic systems and pistons that sent them
tumbling back to Earth for impact 350 Kilometers downrange from the
launch site.With
the boosters gone, the RD-108A engine of the core stage continued
firing, delivering 101 metric tons of thrust to push the Soyuz out of
the atmosphere. Just before passing T+4 minutes, the Soyuz jettisoned
its protective payload fairing after having exited the atmosphere,
making it safe to expose the Glonass satellite.

*File Image* - Photo: Russian Ministry of Defence

*File Image* - Photo: Russian Ministry of Defence

The Core Stage of the Soyuz shut down at T+4 minutes and 45 seconds, having burned through 91,500 Kilograms of propellants. Two seconds after engine shutdown, the RD-0124 engine of the third stage was commanded to ignite split seconds before the stage separation system was fired to allow the third stage to continue powered flight and push the spent core stage away. Shortly after the hot-staging sequence was complete, the third stage jettisoned its aft section to fully expose the propulsion compartment.The RD-0124 engine of the third stage delivered 30,000 Kilogram-force of thrust over the course of a burn of four minutes and 29 seconds, using 25,400 Kilograms of LOX and Kerosene. Just after the T+9-minute mark, the Fregat Upper Stage was separated into a nearly orbital trajectory. Soyuz 2-1B/Fregat theoretically has enough performance to deliver two Glonass-K satellites into orbit which will be done as soon as the Glonass-K2 satellites enter operational deployment. With this launch only carrying a lone satellite, the mission had plenty of excess performance, requiring only a short initial Fregat burn to enter an orbit.

The Fregat Upper Stage is 3.35 meters in diameter and 1.5 meters long, holding over five metric tons of hypergolic propellants - Unsymmetrical Dímethylhydrazine fuel and Nitrogen Tetroxide oxidizer. Fregat is an autonomous Upper Stage that is equipped with its own power, propulsion and control system to perform flights of up to 48 hours. The S5.92 engine of the upper stage is capable of operating at two thrust settings - 2,025 Kilograms and 1,430 Kilograms.The third stage of the Soyuz remained on a sub-orbital trajectory heading for re-entry over the South Pacific. To avoid re-entry, Fregat had to raise the perigee of its insertion trajectory. The Fregat upper stage was set for a short coast of about one minute before conducting a main engine burn of just under 30 seconds to enter an orbit of around 200 by 240 Kilometers. Overall, the mission called for three Fregat burns to deliver the Glonass spacecraft into its target orbit.

*File Image* - Photo: Roscosmos

Following the short first burn, the stack coasted in orbit for just a few minutes to set up the proper apogee/perigee positions for the elliptical transfer orbit. The second Fregat burn was planned to be about 9.5 minutes in duration to raise the apogee of the orbit to over 19,100 Kilometers to enter its Transfer Orbit.In its elliptical transfer orbit, Fregat coasted for about three hours to climb all the way up to apogee so that the third burn could serve as a circularization maneuver. This burn had a planned duration just shy of four minutes, targeting an orbit at 19,130 Kilometers in altitude. After the third burn, Fregat completed a re-orientation maneuver before releasing the Glonass-K1 satellite three hours and 33 minutes after liftoff (Monday at 1:25 UTC). Fregat was to conduct post-separation maneuvers before making a disposal maneuver. Confirmation of mission success was provided after teams established contact with the Glonass satellite, verifying that separation was nominal and the satellite was in good condition.The Glonass-K1 #12 satellite will complete several weeks of testing before joining the operational Glonass fleet where it will replace an aging satellite that is approaching the end of its operational life. The performance of the two Glonass-K1 satellites will be monitored to clear the Glonass-K2 satellites for operational deployment beginning in the coming years as the Glonass-M satellites are phased out. It is planned that the transition from Glonass-M to the next generation of satellites is complete by 2021.

Glonass K1

Glonass is the Russian Satellite
Navigation System which is the counterpart to the US Global Positioning System,
the European Galileo Satellite Constellation and the Chinese Beidou Satellite
Navigation and Communication System. It is being used by the military as well
as commercial customers using open and encrypted signal architecture. The
system provides real time position and velocity determination at an accuracy
that can be compared to that of GPS.

Glonass-K is the follow-on to the improved Glonass-M satellites,
switching from an older pressurized satellite bus to modern unpressurized
systems leading to a significant reduction in mass. Transitioning to modern
spacecraft systems also extends the satellite’s operational life by several
years which will make the maintenance of the constellation easier.

Image: ISS Reshetnev

The Glonass Program started back in 1976 when development was initiated. The first Glonass launch took place in 1982 and the constellation became fully operational in 1995. Over the years, the constellation was reduced as satellites failed and were not replaced.

Photo: ISS Reshetnev

Glonass-M

Later, an effort the restore the satellite fleet was started after funds were made available to the Russian Space Agency. Improved Glonass-M satellites were introduced in 2003 as the constellation was replenished with satellite trios launched on Proton and single spacecraft delivered to orbit by the Soyuz. In 2011, the full constellation for global Glonass Coverage was restored and several launches per year are performed to maintain the constellation and introduce upgraded spacecraft such as Glonass-K that will be launched from 2014 to 2025 before being replaced by Glonass-KM. As part of the program, spare satellites are being kept in orbit to ensure the system remains operational and vehicles are replaced on a regular basis. Over the course of the program, the Glonass satellite design was modified and went through a number of generations. Currently, second generation Glonass-M satellites as well as Glonass-K1 satellites are in service while the Glonass-K2 and KM satellites are under development.

The Glonass constellation consists of 24 active satellites for global coverage. The vehicles operate from a Medium Earth Orbit of 19,100 Kilometers at an inclination of 64.8 degrees.

Glonass features three orbital planes with eight satellites evenly spaced in each plane plus at least one spare per plane. The satellites have an orbital period of 11 hours and 15 minutes. Orbiting at an inclination of 64.8 degrees allows Glonass to provide coverage to high latitudes which can be difficult with GPS that operates at a 55° inclination leading to lower passes for high-latitude areas.

To be provided with position data, a receiver needs to be within range of four Glonass spacecraft.Three are used to determine the receiver’s location while the fourth is used to synchronize the clocks of the receiver and the three other spacecraft.

The Glonass spacecraft are built by Reshetnev Information Satellite Systems (formerly NPO-PM). The Glonass-K satellite switches from the older Uragan satellite bus that consisted of a pressurized compartment to the unpressurized Ekspress-1000K spacecraft platform. The pressurized compartment ensured a simple thermal control of the electronics of the spacecraft by using the gas surrounding the avionics to transport heat to cooling systems. It also allowed components to be flown that were not suitable for the vacuum environment. The Ekspress-1000K satellite platform is a small satellite bus built by ISS Reshetnev to be used for navigation satellites as well as Geostationary Communications Satellite. Glonass-K satellites have a launch mass of 935 Kilograms, about two thirds of the weight of Glonass-M vehicles. The spacecraft features a central satellite body that hosts two deployable solar arrays, each consisting of three panels that use rotation mechanisms to track the sun for optimized power generation. Overall, the arrays generate a total power of 1,250 Watts, 750W of which are used by the payload, the rest is stored in the craft’s onboard batteries for use in eclipse. The central satellite body hosts radiators for thermal control.

Photo: ISS Reshetnev

First Glonass-K1 Satellite

The Glonass-K satellites use state of the art attitude determination and control systems, capable of pointing the nadir panel of the satellites to the correct Earth-facing position with an accuracy better than 0.5 degrees. A chemical propulsion system is used for orbital maintenance and stationkeeping within the Glonass constellation.

The 260-Kilogram navigation payload of the satellite consists of a series of L-Band antennas and associated transmitter electronics, signal generators and Caesium atomic clocks that build the heart of the satellite, delivering the ultra-stable time signals needed to generate the navigation messages. The new Glonass-K satellites are fully compatible with the navigation signals provided by the Glonass-M spacecraft, but add additional signals to improve the accuracy of the system and provide additional services.Glonass-K continues to transmit the existing FDMA (Frequency Division Multiple Access) signals in the L1 and L2 band with two civilian signals and two military signals with higher accuracy. The Glonass-K1 satellites are introducing CMDA (Code Division Multiple Access) signals in the L3 Band that will be expanded to L1 and L2 CDMA signals when Glonass-K2 becomes operational. The final Glonass-M satellites to be launched beginning in 2014 also include the initial L3 CDMA signal. Full Interoperability CDMA signals will be implemented in the 2020s when Glonass-KM is introduced.Each Glonass satellite transmits L1 FDMA (Frequency Division Multiple Access) signals on one of 15 channels with frequencies of 1,602 MHz + n x 0.5625 MHz where n is the channel number. The signals are right-hand circular polarized and are transmitted into a 38-degree cone. With 24 active spacecraft plus spares, most of the 15 channels are used twice creating antipodal satellite pairs with the same frequency (two satellites positioned opposite in their orbit around Earth so that the two are never in the same view from a user terminal).The L2 navigation signals also use the FDMA technique transmitting at 1,246 MHz + n x 0.4375 MHz. The L1OF and L2OF signals are part of the standard service while the L1SF and L2SF signals are used by authorized users only. Glonass transmits this restricted signals in the open, not employing encryption like GPS does.The L3 CDMA signal allows an easy and low-cost implementation of multi-standard GNSS receivers. The L3OC signal is centered at 1,202.25MHz using BPSK(10) modulation for the data and pilot components. The Glonass-K satellites have an operational life of 10 to 12 years compared to the 7-year design life of the Glonass-M spacecraft which will reduce the number of satellites that need to be launched per year in the maintenance of the constellation. Due to their lower mass, Glonass-K satellites can be launched as duos atop the Soyuz rocket and Proton’s capability is six Glonass-K per launch, although no Proton launches of Glonass-K are currently planned.

Image: Roscosmos/TSNIIMASH

Image: Roscosmos/TSNIIMASH

Image: Roscosmos/TSNIIMASH

﻿﻿Soyuz set to Launch Prototype Glonass-K1 Navigation Satellite﻿﻿

November 29, 2014

*File Image* - Credit: Roscosmos

A Soyuz 2-1B rocket is standing tall atop its launch pad at Site 43/4 of the Plesetsk Cosmodrome, Russia for the launch of the second Glonass-K1 navigation satellite set for Sunday night at 21:52 UTC. This is the second of two Glonass-K1 satellites to be launched, serving as a pathfinder for the future generation of Glonass-K2 satellites that are replacing the older Glonass-M satellites to improve the current navigation capability and add new signals to enhance the overall capabilities of Russia’s global navigation satellite system.

The first Glonass-K satellite was launched on February 26, 2011 after being delayed for several years. This new generation of Glonass satellites switch from an older pressurized satellite bus to the unpressurized Ekspress-1000K bus built by ISS Reshetnev, reducing the mass of the satellites from 1,500 to just 935 Kilograms which will allow two spacecraft to be launched atop a Soyuz rocket once the K2 satellites are declared operational. The use of modern satellite technology will also increase the operational life of the Glonass-K satellites which will lead to fewer replacement and maintenance launches needed per year.

The launch of the second of the two Glonass-K1 satellites (#12) was expected in 2012 but slipped into 2013 due to problems with the satellite and its upper stage. In the wake of the 2010 and 2013 Proton launch failures leading to the loss of two triplets of Glonass-M satellites, Glonass operators were dealing with the backlog of Glonass-M replacements that took priority over Glonass-K to keep the constellation operational. Glonass-K1 eventually slipped into late 2014.

In addition to demonstrating the new satellite bus, the Glonass-K1 satellites are also testing CDMA signals in the L3-Band that are being introduced in the Glonass system to become operational with the inauguration of Glonass-K2 that will also feature CDMA signals in the L1 and L2 frequency bands. The upgrade of the Glonass constellation to the K-type spacecraft is expected to be complete by 2021.

With an architecture similar to the U.S. Global Positioning System, Glonass requires 24 active spacecraft in three orbital planes with at least one spare per plane to ensure a continuity of service in the event of a problem with one spacecraft.

The Glonass-K1 #12 satellite was delivered to the Plesetsk Cosmodrome on November 5 to begin final processing ahead of its launch. Once at the launch site, the spacecraft underwent inspections and stand-alone testing. Extensive electrical testing has been completed and the satellite was loaded with propellants for its mission.

Assembly of the Soyuz launch vehicle has also been completed over the past weeks and the Fregat upper stage completed its processing flow that included functional tests and inspections. After Fregat was loaded with hypergolic propellants, the Glonass satellite was installed atop its upper stage before the stack was encapsulated in the protective payload fairing of the Soyuz.

Photo: ISS Reshetnev

Next, the upper composite was installed on the third stage of the Soyuz before being integrated on the Core Stage of the launcher that had its four strap-on boosters already attached.

Countdown operations are expected to get underway on Sunday, about 8 hours ahead of the planned liftoff time of 21:52 UTC. Soyuz 2-1B will complete a nominal ascent mission of over nine minutes, delivering the Fregat Upper Stage and Glonass satellite into a trajectory that is nearly orbital. Launching a single Glonass-K satellite atop a Soyuz 2-1B rocket can certainly be described as a waste of performance since the launcher would be capable of launching two of the satellites. It is likely that the launcher was originally ordered for a dual Glonass-K2 launch since orders are made about five years in advance when it was believed that Glonass-K2 would be operational by late 2014.

*File Image* - Photo: Russian Ministry of Defence

With Soyuz delivering the stack to its planned trajectory, it will be up to Fregat to conduct three main engine burns to boost the Glonass-K1 satellite to its operational orbit over 19,100 Kilometers in altitude. The first burn will be just about 20 seconds in duration to place the stack into an orbit of about 200 by 240 Kilometers at an inclination of 64.8 degrees. After a short coast phase to set up the proper location for the apogee/perigee of the orbit, Fregat will re-ignite its S5.92 engine on a burn of nine and a half minutes to raise the apogee of the orbit to nearly 19,150 Kilometers before entering a three-hour long coast phase to climb all the way to apogee.

Reaching the high point of its elliptical transfer orbit, Fregat performs its third burn, lasting just shy of four minutes to raise the perigee and circularize the orbit at an altitude of 19,130 Kilometers for spacecraft separation a little over three and a half hours after liftoff.

Because this launch is a military mission, no webcast will be provided and information released on the progress of the mission will be limited.

Please consider supporting this website by making a small donation. Our reader's support keeps the site open & improving.